[HDU2222] Keywords Search && AC自动机

来源：互联网发布：淘宝定制怎么弄编辑：程序博客网时间：2024/05/17 23:58

关于last的理解记录的是上一个和当前部分前缀相同的单词节点编号用于快速查找

#include<cstdio>#include<algorithm>#include<cstring>#include<iostream>#include<queue>#define SF scanf#define PF printf#define max(a, b) ((a) < (b) ? (b) : (a))using namespace std;typedef long long LL;const int MAXN = 10000;const int MAXL = 10000 * 50;const int SZ = 26;char s[MAXL*2+10];int ans;struct Aho_Corasick{int ch[MAXL+10][SZ], Ncnt, val[MAXL+10];int f[MAXL+10], last[MAXL+10];void init() { memset(ch[0], 0, sizeof(ch[0])); Ncnt = 1; memset(last, 0, sizeof(last)); }void New() {memset(ch[Ncnt], 0, sizeof(ch[Ncnt]));val[Ncnt] = 0;}inline int ID(char c) { return c - 'a'; }void insert(char *s, int pos){int u = 0, n = strlen(s);for(int i = 0; i < n; i++){int c = ID(s[i]);if(!ch[u][c]) {New();ch[u][c] = Ncnt++;}u = ch[u][c];}val[u]++;}void getFail(){queue <int> q;f[0] = 0;for(int c = 0; c < SZ; c++){int u = ch[0][c];if(u) { f[u] = 0; q.push(u); last[u] = 0; }}while(!q.empty()){int r = q.front(); q.pop();for(int c = 0; c < SZ; c++){int u = ch[r][c];if(!u) { ch[r][c] = ch[f[r]][c]; continue; }q.push(u);int v = f[r];while(v && !ch[v][c]) v = f[v];f[u] = ch[v][c];last[u] = val[f[u]] ? f[u] : last[f[u]];}}}void add(int j) {if(j) {ans += val[j]; val[j] = 0; add(last[j]);}}void solve(char *s) {int n = strlen(s), j = 0;for(int i = 0; i < n; i++){int c = ID(s[i]);j = ch[j][c];if(val[j]) add(j);else if(last[j]) add(last[j]);}}}ac;int main(){int T; SF("%d", &T); while(T--) {int n; SF("%d", &n);ac.init(); ans = 0;for(int i = 1; i <= n; i++) {SF("%s", s);ac.insert(s, i);}ac.getFail();SF("%s", s);ac.solve(s);PF("%d\n", ans);}}/*5shehesayshrheryasherhs */

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